The Internet may feel like it’s everywhere, but large pockets of sky, swathes of land and most of the oceans are still beyond a signal’s reach. This of course, may be something you are actually quite pleased about, given that airplanes, boats and the occasional peak seem to be some of the few places left where you can get some peace.

But not everyone looks at it like that. Three decades after the first cellphone went on sale half the world remains unconnected. For some it costs too much, but some 1.4 billion people, live without even basic network infrastructure.

And then there are the places that for now don’t seem important, but will be: like the oceans. We may not spend much time below the seas that cover more than two-thirds of the planet but increasingly we realise we need to: climate recording, pollution control, predicting natural disasters like tsunami, monitoring oil and gas fields, protecting harbours. And if China gets its way quite a few of us will live down there if only to stake territorial claims to the seas above or the riches below.

So, these all present interesting technological challenges. Not least because most of the people presently unconnected are too poor for the big telcos to worry about. Surprisingly, perhaps, it’s the Facebooks and Googles of this world who are interested, partly because of philanthropic goals but mostly because they’re the last bunch of people who don’t have Gmail and Facebook accounts.

So Google are launch balloons. And Facebook are considering drones. These, though are experimental, leaving an opportunity for niche players like Kacific, which is aiming to build a satellite network it says will provide cheap communications to some 40 million people from eastern Indonesia to the Pacific islands.

Others are finding cracks in the existing technologies and spectrum to forge their own mini telcos. Like Endaga, a Berkeley startup which has used part of the GSM spectrum to build a village level network in a Papuan village.

Some say there’s no need of a network at all. Using a technique called mesh, they string together devices — handphones, or laptops or whatever — which become both nodes and transmitters, meaning they not only do what a device would normally do on a network, but they also help pass on signals to others.

That removes the need for lots of fancy infrastructure like towers, base stations and dishes. Activists in Nigeria have used mesh for lobbying against the demolition of slums, and the technology is being tested by the New Zealand Red Cross. Mesh networks aren’t necessarily small, rural and poor: Athens, Berlin and Vienna have them, too.

Then there’s underwater. Soon our internet will be as much a network of devices as of people with devices. The so-called internet of things, or machine to machine, or whatever you want to call it. Cisco reckons there will be 2 billion such connections by 2018. Connecting these things above ground by wireless is fine but underwater is another thing.

Using the same overground wireless methods for underwater communications isn’t possible, because light travels badly in water. Although technologies have improved greatly in recent years, underwater modems still rely on acoustic technologies that limit speeds to a fraction of what we’re now used to.

This is gradually getting solved, but slowly. Noisy things like pistol shrimps, whose oversized claw snaps a bubble of hot air at its prey, confuse underwater modems.

The oceans and the deserts and mountains and jungles will all eventually get their wireless signals. And we’ll be the better for it. But because of money, and technology, and pesky things like shrimps, it’s not about to happen any time soon. One day we’ll look back and wonder why it took us so long.